using System.Collections;
using UnityEngine;

namespace AibisDream.SaveSystem
{
    /// <summary>
    /// 将 <see cref="SaveSnapshot"/> 逐项写回运行时（纯内存，不读盘）。
    /// <para>
    /// 顺序：Yarn 变量 → 各 Provider（按 RestoreOrder）→（可选）锚点重进节点。
    /// 完整淡入淡出时序由 P4 在 <see cref="SaveRestoreOrchestrator"/> 扩展。
    /// </para>
    /// </summary>
    public static class SnapshotRestore
    {
        /// <summary>还原 Yarn 变量与各 section；不包含锚点重进（由 <see cref="RestoreAnchor"/> 或上层编排）。</summary>
        public static IEnumerator Restore(YarnVariableStorage storage, SaveSnapshot snapshot)
        {
            if (snapshot == null)
            {
                Debug.LogError("[SnapshotRestore] snapshot 为 null");
                yield break;
            }

            RestoreYarnVariables(storage, snapshot);

            foreach (var provider in SnapshotRegistry.GetOrderedProviders())
            {
                if (!snapshot.sections.TryGetValue(provider.SaveId, out var dto) || dto == null)
                {
                    continue;
                }

                dto = SnapshotSectionDeserializer.Coerce(provider.SaveId, dto);
                yield return provider.Restore(dto);
            }

            if (snapshot.deepRepair != null && snapshot.deepRepair.sections != null
                && snapshot.deepRepair.sections.Count > 0)
            {
                Debug.LogWarning("[SnapshotRestore] DeepRepair 段尚未实现，已跳过（P5）。");
            }
        }

        /// <summary>
        /// 按 <see cref="AnchorSnapshot"/> 重新进入 Yarn 节点，实现「所见即所存」。
        /// 调用前应已完成场景加载与各 provider 还原。
        /// </summary>
        public static IEnumerator RestoreAnchor(SaveSnapshot snapshot)
        {
            if (snapshot?.anchor == null || string.IsNullOrEmpty(snapshot.anchor.nodeName))
            {
                yield break;
            }

            var dialog = DialogController.Instance;
            if (dialog == null) yield break;

            var runner = dialog.DialogueRunner;
            if (runner == null) yield break;

            if (!string.IsNullOrEmpty(snapshot.anchor.yarnProjectId)
                && runner.YarnProject != null
                && runner.YarnProject.name != snapshot.anchor.yarnProjectId)
            {
                Debug.LogWarning(
                    $"[SnapshotRestore] YarnProject 不匹配：当前 {runner.YarnProject.name}，存档 {snapshot.anchor.yarnProjectId}");
            }

            if (runner.IsDialogueRunning)
            {
                yield return runner.Stop();
            }

            yield return runner.StartDialogue(snapshot.anchor.nodeName);
        }

        private static void RestoreYarnVariables(YarnVariableStorage storage, SaveSnapshot snapshot)
        {
            var vars = snapshot.yarnVariables;
            if (vars == null) return;

            storage.SetAllVariables(vars.floats, vars.strings, vars.bools);
        }
    }
}